Bemisia Tabaci
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THE CENTRAL MEDITERRANEAN NATURALIST PERIODICAL ISSUED BY THE SOCIETY FOR THE STUDY AND CONSERVATION OF NATURE FOUNDED 1962 VOLUME 2 PART 3 MALTA, MARCH 1995 A & E Sciberras Library THE CENTRAL MEDITERRANEAN NATURALIST Volume 2 Part 3 Malta, March 1995 CONTENTS Page MIFSUDD. Whiteflies (Homoptera, Aleyrodidae) from the Maltese Islands ....................................................................... 61 EBE1ERM.l. The snail-killing fly Pherbellia cinerella (Fallen) in Malta.................................................................................. 79 The hoverflies of Malta (Diptera, Syrphidae): new records and corrections .......................................................... 81 Notes and new records of the larger Brachycera (Diptera) of Malta .................................................................. 86 TABONE1.T. Othantus maritimus (L.) Hofmannsegg et Link (Fam. Asteraceae) and Crypsis schoenoides (L.) Lamarck (Fam. Poaceae), two new additions to the flora of the Maltese Islands .............................................. 97 MIFSUD D., VIGGIANI G., DANDRIA D., and LANFRANCO E. Whitefly parasitoids from the Maltese Islands ....................... 101 Issued by the Society for the Study and Conservation of Nature (SSCN) P.O. Box 459, Valletta, CMR 01, Malta. Editor: David Dandria. SSCN acknowledges with thanks the finanCial contribution received from the Ministry of Food, Agriculture and Fisheries towards the publication of this issue. The Central Mediterranean Naturalist - Vol. 2 (3) 1995. WHITEFLIES OF THE MALTESE ISLANDS (HOMOPTERA, ALEYRODIDAE) David Mifsudl ABSTRACT Whitefly species collected by the author from the Maltese Islands during 1992-94 are recorded. Prior to this study only two whitefly species were definitely recorded from the Maltese archipelago.During this study thirteen species were found. These were Aleurolobus niloticus Priesner & Hosny; Aleurolobus sp., Aleurothrixus jloccosus (Maskell); Aleurotrachelus rhamnicola(Goux), Aleyrodes proletella (Linnaeus); Bemisia aler (Priesner -& Hosny); Bemisia tabaci (Gennadius); Dialeurodes citri (Ashmead); Siphoninus phillyrea (Haliday); Tetraleurodes hederae Goux; Tetralicia ericae Harrison; Trialeurodes lauri Signoret and Trialeurodes vaporariorum (Westwood). A key based on pupal characters is given. For each species, complete collection data, host plant range, global distribution and additional notes are given where appropriate. Attention is drawn to the possible occurrence of other whitefly species with suitable biogeographical distribution and ecology. These include: Aleurolobus olivinus (Silvestri), Aleurotuba jelinekii (Frauenfeld), Aleuroviggianus adrianae Iaccarino, Aleyrodes elevatus Silvestri and Aleyrodes Ion ice rae Walker. INTRODUCTION Several floristic and faunistic studies have been carried out in the Maltese Islands. Due to the critical geographical position of the Islands in the Central Mediterranean Basin, such studies throw light on important aspects of biogeography. Lack of infonnation on the Maltese Stemorrhynchous fauna encouraged the present author to carry out a study of the Aleyrodidae of the Maltese Islands, as the subject of his B.Sc. dissertation (Mifsud, 1993). 1 Department of Agriculture, Research and Development Centre, Ghammieri - Marsa, Malta. 61 Faunistic and ecological studies on whiteflies have been conducted in several Mediterranean countries including Egypt, Israel and Italy, the latter being thoroughly investigated by Italian entomologists in the past twenty years (Mineo & Viggiani, 1975; Iaccarino, 1976; 1981; 1982; 1985; Iaccarino & Tremblay, 1977; Genduso & Liotta, 1980; Patti & Rapisarda, 1981; Rapisarda, 1982; 1985; 1990; Rapisarda & Patti, 1983; Barbagallo et al., 1986). Published work on Maltese whitefly species is limited and only species of agricultural importance have been reported. Borg (1922) pointed out that the citrus whitefly Dialeurodes citri (Ashmead) had never been observed on citrus groves in the Maltese Islands. The earliest Maltese whitefly record was due to Borg (1935) citing the cabbage whitefly Aleurodes brassicae [ = Aleyrodes proletella (Linnaeus)] as a pest on cabbages. An article (Anon., 1985) contributed by David Dandria (pers. comm.) mentioned the newly introduced woolly whitefly pest Aleurothrixus jloccosus (Maskell). In another publication (Vella, 1993) problems caused by this pest in local citrus groves were described. The occurrence of a plant virus new to Malta, the tomato yellow leaf curl virus (TYLCV), mainly transmitted by the sweet potato whitefly Bemisia tabaci (Gennadius) was recently highlighted (Anon., 1993a; 1993b; 1993c). Problems caused by this virus were also recorded by Saliba (1993). METHODS Field investigations and collection in several habitats of the Maltese Islands were conducted by the author during the years 1992/94. All identifications were based on the pseudopupal stage. Fig.l shows a diagramatic representation of a whitefly pupal case. Species not covered in author's dissertation (Mifsud, 1993) are indicated by an asterisk (*). 62 ANTERIOR VENTRAL DORSAL SURFACE SURFACE TTF I _--Ma I I TTPA-- / ~p / /""--TS 1 - - -SMA /----TS 2 C-...-_ 1 / R-_ --........ '''''''CR ~~-,~~~, "S "- 0- CaS--! -ATF L-- ArPA POSTERIOR ---CF Fig.l - General morphological characteristics of a whitefly puparium. A, antenna; Abd S, abdominal sutures; AMS, anterior marginal seta; AS I,ll, anterior, posterior abdominal spiracle; AS 1,8, 1st, 8th abdominal seta; 1-8 abdominal segments; AS, adhesive sac; ATF', abdominal tracheal fold; ATPA abdominal tracheal pore area; BMS, basal minute seta; C, crenations; CaS, caudal seta; CeS, cephalic seta; CF, caudal furroW; CR, caudal ridge; DDA, dorsal disc area; DMS, distal minute seta; DP, disc pore; IP, internal pocket; L, ligula; Ll,2,3 pro-, meso-, metathoracic legs; LC, lateral carinae of vasiform orifice wall; LS, ligular seta; M, mouth parts; Ma, margin; 0, operculum; P, porette; PMS, posterior marginal seta; PVT, posterior vasiform tubercle; R, rim; S, spinules; SDA, subdorsal area; SF, submarginal fold; SMA, submarginal area; SMD, submedian depressions; SMP, submaginal papilla; Sp, spine; SP, simple pore; SR, submarginal ridges; TC, tubercle cluster; 1MS, transverse mOUlting suture; TS1,2, meso-, metathoracic setae; TSI,I1, anterior, posterior thoracic spiracle; 1TF, thoracic tracheal fold; TTPA, thoracic tracheal pore area; V, vasiform orifice; VAS, ventral abdominal seta. 63 KEY TO THE WHITEFLY SPECIES OF THE MALTESE ISLANDS - BASED ON PUPAL CASES (species not in bold type have not yet been found in the Maltese Islands, but have been included since their occurence or possible introduction is highly probable) 1. Pupal cases evenly brown or lack. ................................................................... 2 Pupal cases wholly or partly with pale to dusky cuticle ................................... 6 2. Wide submargin separated from dorsal disc by a distinct furrow (dorsal surface) .......................................................................................................... 3 Submargin not physically separated from dorsal disc ...................................... 5 3. Outline subcircular, little longer than wide. Larger species, female puparia up to 1.70mm................................................. .... Aleurolobus olivinus ( Silvestri) Outline oval, conspicuously longer than wide. Smaller species, female puparia up to 1.30mm................................................................................................. 4 4. Operculum acute posteriorly. Margin at thoracic tracheal openings with three modified teeth; remainder of margin with regular, shallow crenulation ............ ....................................................... Aleurolobus niloticus Priesner & Hosny Operculum rounded posteriorly. Margin at thoracic tracheal openings unmodified; remainder of margin irregularly but coarsely crenulate ................ ............................................................................................... Aleurolobus sp. 5. Pupal case with margin deflexed ventrally, rendering edge ofpuparium a "false margin" which is smooth. Outline rather irregular, much longer than wide ....................................................................... T etralicia ericae Harrison Margin not deflexed, with regular fine teeth. Outline suboval, widest at abdominal segment III. Inner subdorsum with a pair of folds, concentric with margin, from thorax to abdominal segment 11. ................................................. ............................................................... Aleurotrachelus rhamnicola (Goux) 6. Wide submargin separated from dorsal disc by a distinct furrow ..................... 7 Submargin not physically separated from dorsal disc ...................................... 8 7. Submarginal furrow interrupted posteriorly, not present behind vasiform orifice. Cephalic, meso- and meta thoracic, eighth abdominal and caudal setae present,short and stout. ...................................... Tetraleurodes hederae Goux Submarginal furrow continuous behind vasiform orifice. Metathoracic, eighth abdominal and caudal setae only present, long and hair-like, wavy .................. ................................................................. Aleurothrixus jloccosus (Maskell) 8. Outer sub margin with an even row of 14 pairs of fine setae up to 45 J.l.m long. Head oflingula with a pair of lateral processes basally .................................... ..............................•.......................................